this is my first reaction too. I don't see how this makes it easier for the consumer. I don't especially want to type my user name and password into one of those terminals.
Customer: "cappucino please"
employee: "Paul, right?"
customer: "yes"
employee: "decaf and skim, as usual?"
customer: "yes, thanks"
employee: "ok, you've paid by square"
The partnership didn't mention pay by name, but I can't imagine the partnership is really meaningful without it. This could spur widespread adoption of pay by name. When people start doing this at Starbucks, it will quickly seem like a normal way to pay, and using a card may start to seem clunky.
I guarantee that typing in a PayPal account number is hella clunky, and NFC little better. Do I reall want to unlock my phone to buy coffee?